Sardion

The Sardion, or Cthrag Sardius, was the opposite of the Orb of Aldur and the other half of the stone at the center of the world. The Sardion was larger than the Orb, an "oblong stone somewhat larger than a man’s head", and described as "streaked with pale orange and milky white in alternating stripes banded closely together" in color. It glowed (dusky) red. When in close proximity with the Orb, it made the Orb burn red.

After falling from the sky, for centuries it was housed in an underwater temple in Zamad, one of the seven kingdoms of Karanda, where it was worshiped. At the beginning of the third millennium, a King of Zamad assimilated Veresebo and the Melcene emperor mounted a punitive expedition into Zamad to teach the Karands a lesson. The Melcene emperor took the Sardion (which Senji speculates more to punish the Karands than out of any desire to possess the stone for himself). Later, the Melcene emperor donated the Sardion to the University of Melcene, where it became part of the museum of College of Comparative Theology. It was moved by the Melcene scholar in the College of Arcane Learning to "The Place Which Is No More," at the time of the Battle of Vo Mimbre.

"Sardius" is the Latin word for sard, a variety of red chalcedony which was popular as a gemstone in the ancient Near East. The name thus relates to the red colour and the milky and clouded appearance of the Cthrag Sardius stone in the book.